Our objective in these studies is to obtain information on the structure, localization, metabolism and functional roles of glycoproteins in nervous tissue. Most of these complex carbohydrates in brain are present in membranes and on the cell surface, where they are thought to mediate various types of cell-cell interactions such as intercellular adhesion and synaptogenesis. Brain glycoproteins may also be involved in regulating the electrical and chemical excitability of neural membranes, and as receptors for neurotransmitters, drugs and hormones. In order to provide the foundation of basic neurochemical data which will be necessary for understanding their functional roles, we plan to extend our investigations to a detailed analysis of the structure and metabolism of glycoproteins present in purified plasma membranes isolated from highly enriched preparations of neurons and astrocytes, and from nerve endings. Other studies will concern the structures of a series of novel mannitol-containing oligosaccharides derived from a chondroitin sulfate proteoglycan which we have demonstrated to be present in the neuronal cytoplasm, and further characterization of complex carbohydrates from the soluble contents and membranes of adrenal chromaffin granules, where they may play a role in the storage and release of catecholamines.